Improvement in the manufacture of gas from coal



UNITED STATES PATENT OFFICE.

DARIUS DAVISON, OF NEW YORK, N. Y.

IMPROVEMENT IN THE MANUFACTURE OF GAS FROM COAL, &c.

Specification forming part of Letters Patent No. 148,188, datedMarch 3, 1874; application filed September 3, 1873.

To all whom it may concern:

Be it known that I, DARIUS DAVISON, of the city, county, and State of New York, have invented a certain new and useful Improvement in the Manufacture of Gas from Coal and other substances, of which the following, is a specification:

This invention consists in a novel process of manipulatin g retorts for themanufacture of illuminating-gas, and the charges of coal and the residual coke, whereby I am enabled to obtain an increasedquantity of gas from a given amount of coal distilled; and a better quality of gas is produced from charges of coal in the retort, of anyrequired amount and at any required period of distillation, without, or of necessity, involving any change in the construction of the apparatus now used, excepting, if convenient, having duplicate or extra light sheetiron lids to temporarily close the mouth of the retorts, for the purpose of excluding the air after the charge is drawn, so as to admit of the retorts being heated, while empty, to a proper temperature before a succeeding charge is placed therein for distillation. These lids may be used without luting, or the ordinary lids, with or without luting, maybe employed instead.

To illustrate and more fully explain the objects and effects of myimproved process, I will briefly refer to the mode heretofore and now practiced of operating retorts, and the effects thereof. Ordinarily the usual charge of coal is placed in the retorts, and the period the distillation is continued-say, four, five, or six hours, more or less-is dependent upon the heat of the retorts and the amount of the charge to be distilled. The coke, however, re mains in the retorts during the whole period of distillation, causingit to consume a large percentage of the heat required to reheat the retort or retorts for the succeeding charge without any useful effect whatever, and during the latter portion of the period-generally varying from half an hour to one hourthe coal or coke is thus exposed there is necessarily distilled from it a limited quantity of very poor gas,-having no illuminating property, and which mixes with the rich illuminatin g-gas produced during the early distillation of the charge. This detrimentally reduces the illuminating quality of all the gas derived from the charge, inasmuch as the small increase in the volume of gas so obtained is very much more than counterbalanced by the deterioration in quality, which is an important consideration in the manufacture of illumin ating-gas.

I will now proceed to describe, in detail, my process or mode of manipulating gas-retorts, and the coal and coke therein, together with the'resulting effect-s thereof-namely, of increasing the quantity and quality of the gas without the same being due to the quality of coal usedthus effecting the best distillation, inasmuch as the quality of the gas, which is an all-important element in all gas manufacture for illuminating purposes, is improved, as well as the quantity of gas increased, from or by the distillation of a given quantity of coal.

Retorts to be operated by my process are first heated to a certain temperature, which may vary from a low to a high white heat, according to the amount of the charge designed to be distilled at any period of time, varying from four to six hours, more or less. Supposing, however, the time of distillation is fixed at five hours, I regulate the heat so that all the good gas obtainable from the charge would be exhausted in about four-and-a-half hours, more or less, and, upon this result being obtained, and without waiting for any further distillation from the charge, and before reheating the retort for a succeeding charge, I open the retort or retorts and withdraw the coke in the condition it then is, being at a low heat. The ordinary or any suitable lid, with or without lutin g, is then temporarily applied to close the retort for the purpose'ot excluding the circulation of air within the retort or retorts, thus operating to cool the same, and the retort thus closed is allowed to stand empty in the hot oven-say, half an hour, more or less, in a five-hour distillation-i0 become quickly and highly heated to the desired temperature for the proper distillation of the succeeding charge. By this means a sufficiently-high temperature is quickly obtained to produce an active and proper distillation of the rich vapor from the coal, and conversion of the same into gas, in the early part of the distillation of the whole charge, and a more thorough or nearly complete conversion of such large volume of rich vapor into permanent gas before it passes from the retort or retorts. In this way there is both an increase in quantity and improvement in quality ofthe gas, and less of the luminous burning carbonaceous oils distilled from the coal in the early part of the distillation escapes from the retort, in a vaporous condition, from want of sufficient heat, to be subsequently condensed in the stand-pipes and hydraulic main, and pass off wastefully into the coal-tar.

By withdrawing the charge from the retort, after all the good illuminating-gas is distilled, and the residual coke is at a low temperature, and afterward temporarily closing the empty retort while the latter is being heated for the succeeding charge, no poor gas is made as a deteriorating element of the good illuminatinggas produced in the early part of the distillation. Heat also is economized by reason of the residual coke of the one charge not being allowed to remain in the retort and absorb heat while the retort is being heated for the next charge. Time, too, is economized in the distillation, or in a succession of distillations, for the reason that the heat can be kept up in the retorts, to the required degree, to produce the best results, in less time, between the charges, than in the usual mode of procedure,

by the higher heat being more quickly obtained with the best effect during the early stage of distillation, when the largest and richest flow of gas and vapor is produced in the retorts subject to the proper heating of the latter during that time.

I claim as my invention, and desire to secure by Letters Patent- The process, substantially as herein described, of manufacturing illuminating gas from coal or other substances, by withdrawing the residual coke or material of one charge from the retort or retorts when all the good illuminating-gas has been distilled therefrom, and while the residual coke in the retort or retort-s is at a comparatively low temperature, and the non-luminous gas has not been distilled therefrom, then temporarily closing and reheating the retort or retorts, while empty, to the necessary degree, to properly distil the succeeding charge, and then recharging the retort or retorts, in time and manner described,

as a regular, systematic, continuous mode of operation, for the purpose or purposes herein set forth.

DARIUS DAVISON.

\Vitnesses FRED. HAYNES, FERD. TUSCH. 

